mar104 from Lloyd Erlick,

I've had exactly the same experience. ("Since the
mat can not slide under the clips when it swells,
it buckles between the clips.")

And, indeed, "Once buckled there seems to be no
cure." Sadly, this included getting the commercial
framer to acknowledge that buckling existed and
was patterned according to the clips on the back.

Mine had the rust, too.

(My erstwhile framer suggested that I had stored
the frames improperly. Rusting clips suggested
long exposure to clammy, wet, dank dungeons. But I
had done no such thing, and they rusted because
anyone can look at them and see they are a very
cheap grade of steel. Frames from the same framer,
done years before, were unbuckled. They had no
clips. And they were stored in the same type of
environment (above grade in homes with people
living in them.) But you cannot change the opinion
of a framer. They are a separate species adapted
to feeding off the anxiety and rage of
photographers. They should be treated like
mosquitos.)
________________________________
Lloyd Erlick Portraits,
2219 Gerrard Street East, unit #1,
Toronto M4E 2C8 Canada.
                ---
voice 416-686-0326
lloyd AT the-wire DOT com
http://www.heylloyd.com
________________________________

Do you use a backing board?  I'm guessing that the same problem would occur
with or without a backing board.  Maybe I better start checking my frames.
Chuck